Reduction of chemical compounds.



E. WE-INTRAUB.

REDUCTION OF CHEMICAL COMPOUNDS.

Patented Mar. 5

APPLICATION FILED JULY 20, 1910.

Fig.1.

Inventor E-zechiel We'ntraub,

Hus DT ttorneg.

wltnesses y jialeaving a tube of reduced element.

UNITED STATES PATENT OFFICE.

EZECHIEL WEINTRAUB, OF LYNN,'MASSACHUSETTS, ASSIGNOI R. TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

REZOUCTION OF CHEMICAL COMPOUNDS.

To all whom it may concern:

Be it known that I, EZEOHIEL WEIN'I'RAUB,-

a citizen of the United States, residing at Lynn, county of Essex, State of Massachusetts, have invented certain new and useful Improvements in Reduction of Chemical Compounds, of. which the following is a specification.

My present invention relates to the reduction of metals'and metalloids and comprises an improved method and apparatus suitable especially for the production in a pure state of elements such as boron, titanium, thorium, uranium, tungsten, molybdenum, and others.

According to my present invention, a mixture of a volatile reducible compound of the respective element to be reduced, as for example, a halid, is mixed with a suitable reducing gas such as hydrogen. The mixture is brought into contact with a thin refractory tube heated to the temperature of reduction. The reducing action thereby imtiated results in the deposition of the ele- --ment on the surface of the refractory tube.

The reducible mixture is preferably brought into .contactwith the tube on its outer surface, the reduction being continued until a layer of substantial thickness has been deposited. The original tube of refractory material is then removed by. mechanical means The reduction may, however, take place on the inner surface of the refractory tube and may be continued until the tube becomes practically filled with deposited material so that upon removal of the shell there is left behind a solid, or nearly solid, stick of the reduced element.

My invention is also applicable to the production of alloys which result from the addition of a volatile compound of the desired alloying element or elements to the reduction mixture, for example, the process may be employed for the production of boron carbon alloys as described in my application, Serial No. 524,950, filed Oct. 27, 1909. Alloys of different refractory metals may be produced in like manner by employing a mixture of volatile reducible compounds of the same, thereby depositing the metals simultaneously. The process is particularly applicable to the production of pure boron. The boron thus obtained is exceedingly hard, and very strong. 'With it glass may be cut with the same ease as w1th diamond, and even in Specification of Letters Patent.

Application filed July 20, 1910. Serial No. 572,830.

Patented Mar. 5, 1912.

thin sheets it can be broken only with diflFi culty. The process is also useful for the reduction of diflicultly reducible metals, such as titanium in a state of high purity.

An apparatus suitable for producing the effects above outlined is shown in, the accompanying drawings, of which F gure 1 is a sectional elevation of the reduclng chamber and Fig. 2 shows in detail a modified clamp for the heater.

The reduction chamber comprises a gastight envelop, 1, which may conveniently consist of glass, provided at top and bottom w1th insulated terminals 2, 3, passing through rubber stoppers 4, 5, making gas tight joints. The removal of air and other gases from the chamber takes place through 'the tube 6. The terminals are cooled by the passage of a suitable fluid such as water introduced by tubes 7, 8. Clamps 9, 10 serve to make the necessary electrical connections. The tubular terminal 2 is screwed into a copper plate 11 which is attached by .connectmg strips 12 to another metal plate 13. To this plate 13 a graphite clamp 14: is firmly attached by the screw 15 as clearly shown. The tube 16 ending between the two copper plates 11, 13 serves to introduce the by dilfusing out between the plates 11, 13.- The thin-walled heater tube 17 consists of carbon or graphite,.prepared either by carbonizing tubes of paper, or by turning down carbon or graphite tubes to the desired thickness in the lathe. The tube 17 is. .conveniently attached to the clamps byfriction and a small amount of carbon paste. It is attached at its lower end to a graphite clamp '18 dipping into a body of mercury 19 con tained in a small vessel 20 supported by the terminal,3. A small platinum plug 21 attached to the clamp 18 is used to weight the lower-end of the tube, thereby preventing its being broken by the upward pressure of the mercury. The mercury connection is used to enable the tube to readily expand when heated. In some cases it is desirable to support the clamp carrying the upper end of the tube as well in mercury for the purpose of allowing free expansion and contraction. A modified form of connection designed to carry the upper end of the tube in mercury reaction mixture which is then distributed I containinga body of merc'ury 23 in which fioatsa graphite ring- 24,- attached to a-plate' 28, which-carries copper strips 25. These copper strips inturn are attached to "the' plate 13', which supports the graphite clamp 14 holding the tube. v

Means-should be provided foriequalizing the beginningof the.operation. This can be conveniently done by-provldmgsmall holes as indicated at 26 in clamp .18 in'Fig. 1. or

by providing atube -27, communicating with the inside of the tube asshown m Fig. 2. This tube can be ,attachedto' a supply of hydrogen, in order to allowthe -pressure to adjust itself and the connection may be later shut ofl when-the equilibrium in gas pressures has been established.

In an apparatus asdescribed above the process is carried out as follows: Forthe production'oflbor'on, for example, a mixture of reducible boron compound, such as boricv chlorid, andfh ydrogen'is introduced into the chamber 1f :by'fmeans of tube 16, displacing the gas idthe vessel, which may conveniently cons i 'of hydrogen. Current is-then supplied to he heater-tube whlchrl's thereby heated to the-temperaturenecessary. to cause chemical action between the boric chlorid and hydrogen, resulting inthe deposition of boron upon-the surfaceof the tube andthe hydrochloric acid gas which is formation of removed through-the ube -6, together with,

unused hydrogen, ior; any unreduced boric chlorid which mayjiiemain. The reduction is'continuedunti eidesired-thickness of boron has been id sited, the'coated tube is removed and thermaterial of the original tube, which has'fforined av brittle substance consisting of carbon boro'n is removed mechanically. I h v I When it isidesired to depos tan alloy of boron andcarbon'on the tube, a mixture of boric chlorid, hydrogen. and *a volatile carbon compound such as gasolene or carbon tetra-chloridjis. employed, the proportion of carbonaceous gas depending, of course, upon the amount of carbon desired in the alloy.

This simultaneous deposition of the two elements is afconvenient method of producing solidsolutions, oralloys of carbon and boron of any desired predeterminedproportion. As already: indicated alloys of re-. fractory metals lar manner by using "mixtures of volatile compounds of thesame with'hyd'rogen, or ot'herireducinggas;'

In case the reduced 'elementis tode-v posited upon the inside of the tube, the gaseous mixture is admitted to" the inside of the tube through pipe'27, Fig.2, and the hydrogen used-for washing the tube is admitted or withdrawn through tubevl6. The deposit on the inside of the tube can be built up until the passageway becomes enthe gas pressure in theinside of the tube at cally unites with the can be produced in a simiture of.

tirely filled. Thereafter the tubular enveltiip' of carbon and carbid may be ground 0 a substantially solid stick consistboronor of boron associated with leavin' ganother element, in accordance with the chemical-compositlon of the gaseous mixture originally supplied to the 'uniting with the carbon of said tube at' the temperature'to form a brittle maeft'ected from and hydrogen said brittle ma depositin terial, SalCl'dGPOSltlOIl bein 'a mixture of reducible halid and subsequently removing terial. I

. 3. The process which consists in progressively supplying a mixture ofboric' chlorid and hydrogen to a carbon tube heated with current to the temperature at which reduction of the boric chlorid takes place, with deposition of boron on the wall of the carbon tube and chemical union therewith, and subsequently removing the combined carbon and boron 'to leave a dense uniform body of boron.-

4. The process which consists in progressively applying a mixture of reducible gas and reducing gas to the inside 'of a thinwalled refractory tube heated to the tem perature at which 5 reduction occurs, continuing the operation until the tube is substantially filled with-deposited material and then removing said tube to, leave a body of pure deposited material.

An apparatus for the reduction of compounds comprising a thin walled carbon tube, means for supplying current to said tube to heat the same to incandescence, said means including a connection permitting free expansion of said tube with thermal changes, and means for bringing in contact with said tube a mixture of reducible com- I pound and reducing gas.

6. The combination of an envelop, fluid cooled electrical terminals therefor, :1 Sta-- tionary carbonaceous tube arranged in circuit between said terminals, means of wash-' ing said tube with hydrogen and means for bringing into contact with said tube a mixgases chemicallyactive on one another at an elevated temperature.

7. In a reducing apparatus, the combina-- tion of an envelop, mounted therein, means for conducting our rent to said tube to heat the same, said means a fragile heater tube comprising a contact arranged to permit free thermal expansion of said fragile tube, means for bringing into contact with said tube a reduction mixture, and means for washing said tube with hydrogen.

8. In a reducing apparatus, the combination of an envelop, a liquid metal terminal therein, a fragile carbon heater tube having its lower end floating in said liquid metal, and means for supplying a reduction mixture to said envelop.

9. In a reducing apparatus, the combination of an envelop, a refractory heater tube mounted therein, means for supporting each end of the tube and conducting current 15 In witness whereof, I have hereunto set 20 my hand this first day of July, 1910.

EZEOHIEL WEINTRAUB.

Witnesses:

H. C. Coxn, M. S. HINLAND. 

